Here’s an open source library that makes it easy to add drag and drop to UIViews with a number of nice features called AtkDragAndDrop by Rick Boykin.

AtkDragAndDrop makes it easy to set up views as drag and drop source and destination zones, provides a shadowing feature to illustrate a view being dragged, allows you to specify a UIGestureRecognizer for drag recognition, works with the UIPasteBoard for data passing, and a really nice auto-scrolling feature as you drag in a UIScrollView.

Included is an example showing how to set up some basic drag and drop views and zones.

A screenshot of some images from the included example app:

You can find AtkDragAndDrop (Asymptotik Drag And Drop) on Github here.